6
A dentist conducts a survey to find out about the dental hygiene habits of her patients.
Which of the following is the most effective random sampling method for this survey study?
Using patients' last names to pick one patient with a last name that starts with each letter of the alphabet
B Asking 50 patients to fill out the survey and receive a 5% discount
Using patients' ID numbers to randomly select 50 patients and contacting them to fill out the survey
Asking the first 50 patients who visit the office to fill out the survey